I use an Ogio Mastermind. Its not the cheapest ($100 regular, $90 right now on ebags.com), but Ogio will replace it for life. I've had mine for 3 years, and the first one's strap holder (the plastic thing for tightening) cracked after a year of incredibly heavy use, but it was still usable with some caution, and after school was out, I sent it in to Ogio and they had a new one for me in 2 weeks. It has a great laptop pouch that fits up to 17" laptops, but the way it is designed it takes any size lower than that very well also. I use it with my 13" MBP nearly every day, and I use it with just a neoprene sleeve, and no problems thus far. It also has a large pocket that I can fit up to 6 1" binders and 1 3" textbook in, just for reference, though the bag is a bit tighter when you first purchase it, so don't expect that immediately, it does have to break in. It also has a smaller pouch in front of that that can easily fit some folders. In fact, it was designed to hold papers for traveling, and therefore the pocket has 3 dividers in it. Also, it has a smaller front pocket for miscellaneous items, such as keys, gum, etc. There are two smaller pockets on the bottom for the charger and mouse. There are two more even smaller pockets towards the top for other miscellaneous gear, and finally a top pocket with a felt-ish interior for iPods, phones, and the like, with a headphone out hole.
The bag itself doesn't weigh much, but when fully loaded it can get extremely heavy, simply because it can hold so much. I believe it is Ogio's largest bag at the moment. If you really want one, there are about 10 color combinations, but Ogio only manufactures a few at a time. When I bought mine, I saw black, plaid, and red, but now I don't see the red, and there are about 4 other colors on Ogio's site.
